I think you need to amend 2018; to either use the inventory method OR to set up account(s) for purchased but unsold inventory....like a prepaid expense account.
Basically when having items for sale/resale, you can't expense items before they're sold. The unsold goods are basically non-incidental material or supplies and have to be accounted for as such. In either way of accounting for them, you have to reduce the 2018 COS for the unsold items and either account for them as ending inventory or a balance amount in a prepaid materials/supplies.
**Disclaimer: Effort has been made to offer correct information; but due to the discussion forum limitations, the poster disclaims any legal responsibility for the accuracy of the poster's response**
